This instrumentation circuit was found in the September 1989 Radio Electronics magazine. The circuit uses an analog indicator and the power supply must be symmetrical.
The sensor for this alarm is an LDR and it consists of an oscillator that goes into action when...
We found this amplifier circuit for inductive audio pickups in a documentation from the 70s. The...
This circuit is from an American documentation from 1976. The FET can be the BF245 or MPF102 and...